Dual safety valve assembly



c. H. FoLMsBEE ET AL DUAL SAFETY VALVE ASSEMBLY Filed Feb. 18, 1947 Sept2, 1952 \|VLI Patented Sept. 2, 1952 d I UNITED STATES PATENT OFFICE@`DUAL SAFETY vALvE ASSEMBLY Clyde H. Folmsbee, Bloomsburg, 'and JeromeM.

v Mar-tis, Wilkes-Barre, Pa., assignors to American Car and FoundryCompany, New York, N. Y., a corporation of NewJersey ApplicationFebruary 1s, 1947,l serial Ne. 729,26@

' 6 Claims.

This invention relates to safetyvalves in general and in particular todual safety valves intended for use with infiammable or corrosive gasesin storage. V

Inrecent years a large business has developed in the storage ofinammable gases such as butane and propane and corrosive gases such asanhydrous ammonia, chlorine, etc.V These gases are normally stored incomparatively large quantities and over a considerable period of time,with theresult that safety valves of a very dependabletype must beinstalled. It is necessary that these valves be lifted and tested atperiodic intervals and occasionally a safety valve when so tested willdevelop leaks ofsuch a nature that the entire storage tank has to bedischarged and the defective safety valve removed for repair. Sincethesefstorage tanks are usually in populated. areas it is necessary toclose'off and evacuate people from large areasduring the period that thetank is being discharged. This results in tremendous losses andinconvenience to the owner and :neighboring business and people. It isanobject, therefore, of the present invention to provide a safety valvewhich can be removed from the storage tank and completely repairedwithout any significant loss ofmaterial from the tank. f s y A furtherobject of the invention is'the provision of Va dual safety valveassembly for tanks in which Aa part thereof is built into the tank andanother part can be removed from the tank- A stillA further object ofthe invention is the provision of a self contained safety valve whichcan be placed on and removed from a storage tank .while under'pressureand withoutr loss'of material from the tank.VV f

These and other objects ofthe invention will be apparent vto personsskilled in the artzfrom a studyn of the following descripticnandaccompanying drawings, in which Fig. 1 is a sectional View through theimproved valve assembly;

Fig. 2 is a similar sectional View but showing the safety valveinzposition for removal, and' Fig. 3 is a sectional `view takensubstantially on lined-3 of Fig. 2.

Referring now to the drawings in detail i-t will be seen that the dualsafety valveassembly is made up'of a removable partiA and a part B whichis permanently built into the tank and can not be tampered with exceptwhen-the. tank is completely emptied and cleaned. The shell of thestorageftank is indicatedat 2 and 'this shelluis pierced to receive aVtubular nozzle 4 permanently 2 Y welded or otherwise attached as at 6 tothe shell of `the storage tank. This nozzle has welded thereto adjacentits lower or inner end aring 8 and adjacent its upper end is welded aring l0. The lower inner surface of the nozzle is beveled as at I2 andthis merges into a machined surface I4. -The upper end of the nozzle hasitsinterior surface machinedV as at I6 and a small notch or groove I8 iscut so as to provide a vent later to be referred to. Y

The lower ring d carries a plurality of vbolts or Asimilar means 20which are threaded into the ring and welded against movement as at 22.These bolts or similar means provide a thrust surface for the lower endsof spring 24, the upper ends of which bear against a stop valve plate 26guided for movement on the bolts 20. The stop valve plate is providedwith a beveled seating surface 23 adapted to contact with the beveledseating surface I2 of the nozzle. The stop valve is also provided with avertical extension grooved as at '3G to receive a resilient sealing ring32 of circular cross-section, which ring is adapted to lightly'engagethe machined surface i4 to effec'- tively seal against leakage. f

The safety valve consistsof a body 34having anges 36 adapted to beclamped onto the upper end of the nozzle by means of bolts 38 whichextend through a'clamping ring 4i) and into the nozzle ring Ill. Theclamping ring as shown is provided with a discharge stack 42 of anysuitable length. VThe safety valve body `is pierced to provide apassageway 44, rat the upper end of which is provided a valve seat 46adapted to engage a similarly formed seat 48 on the valve'stem member.The valve stem member is provided with'w-ings' guiding it in the bodyopening and the seats 46 and 48 are held in intimate Contact by 'meansof a spring 52 bearing at one end on the valve body and at the other endon cage 54 vadjustably held on the valve stem 56 by nuts or other means58. In order to prevent any leakage past seats 4B and 48 a cap member 60is clamped onto the valve by means of the nut or other means 62 and thiscap is grooved to receive a resilient ring 64 of circular cross-sectionwhich will prevent any leakage past the stem extension of the valve. Asimilar ring S6 of resilient material and circular crosssection isreceived in a groove formed in the cap and this ring engages a portionof the body to prevent any leakage between the cap and body. In thismanner leakage of material through the safety valve is prevented exceptwhen the lvalve should open 'or pop under excessive pressure. The outersurface of the valve body 34 is grooved as at 68 to receive a circularring 10 of circular cross-section and resilient material which isadapted to engage the machined surface I6 of the tank tube or nozzle andthus effectively prevent leakage between the safety valve body and thetank tube or nozzle. A tubular extension'M is welded or otherwiseattached 'tov the inner surface of the valve body 34 and is ofsufficient length as to hold the stop valve assembly 26 from engagingthe lower end of the tank tube or nozzle when the Ysafety valve is inposition. In order to permit ready entrance of material from the tankintothe tubeld semi-T.

circular openings 16 are formedvinthelower-end; thereof.

When the parts are in the position shown in Fig. 1 the safety valvewithits extensionwll.

maintain the stop valve 26 in its full open position or at least in sucha position that an area for passage of material into tube 'i4 isprovided whiehis equal to or greater than the total disdishargearea pastthe safety valve when open or p opped. Ifgfor any reason the safetyvalve should (develop a slight leak ory be ldamaged in any-way-it, .canberemoved by rotating nuts 80 on bolts. ,38gI thereby permitting theinternal `tank pressure-tolift theisafety valve in the nozzle.iis5the-.nu-ts-A till'` are backedeoif of the bolts the safetyvalvewillfollow with all leakage `prevented by the r-esilient ring 10.When the safetyfvalve hasbeen; raised sufficiently the seating surface28 ofthestopvalve will engage the seating surface IZvof :the tanktuberornozzle and further movementofg thestop valvewill be checked. Prior tothisitime. however,- theecircular ring 32 of resilientmaterial willyhave-entered the` nozzle and engagedtheA machined surface I4 thussealing the :1W/er1v end. of the, tank tube or nozzle. Thestopvalvethengbecomes a thrustmember pushing thesafety--valveupwardlywith itsmotion controlled.: by :the rate at; which' the nuts 80 arebackedpf the bolt.- Any pressure trapped within the; tanktube'orgnozzlewill Vcontinue to lift the valve after the -stop valve-has becomeseated. As soon, however, as the resilient ring 'Illhas passedthellvower enclofv groove I8 this trapped pressure wllgbelvented; andthenuts 8l) may be thenfully removed without danger. As soon as these nutsare removed thefstack audits. ringllly be removedgandi the; ent1e safetyvalve removed f0.1* inspection; and. necessary repair- Afterinspectionand'repair the 4.safety valvel may be again insertedjnto thetank 4tube vor nozzlewith the resilient;Y ring-I8 sealing` against anyescape of material. between the. nozzleand valve body. Forcing; ofithesafety valve into its final position will be-accomplishedby'tightening the nuts 8D o ntothebolts 38, thereby forcing the safetyvalve intdzits nal position'during which time the stop yalveffwillbemoved to its open positionias lshown in VEiga'. 1l

lroimtheprecedingit will be seen thatthe stop valve isattachedV to thetank tube or nozzle; on the inside of .thetank andprevents escape ofgasorfmaterialh from the; tank when the safety-valve iseremoved.-` Itwillalsobe apparentthat the safety-valYe-can be removed, repaired andreinserted-inthe tube or'nozzel without any danger or,loss-of materialother thanvtheloss of'the Small amount ofmaterial which is trappedwithingthestanktube or nozzle at the time of closing thefstopvalvey 26.Whilevthe construction has heendescribed more or-less in Vdetail withspecic reference tothe drawings. it will be obvious thatalightmodifications; may-be made without de- 4 parting from the scope ofthe invention as defined by the following claims.

What is claimed is:

1. A dual valve construction comprising, a nozzle structure, a pressurerelief valve assembly having atleast portions thereof located within thenozzle structure, means, retaining said pressure relief valve assemblyportions in said nozzle structure and adapted to allow removal of saidassembly, sealing means interposed between said assemblyv and nozzlestructure to prevent leakage therebetween during at least part of theremovalmovement of said pressure relief valve assembly. a stop valvecarried by said nozzle structure adjacent the inner end thereof, anextension on said pressure relief valve assembly holdingk said stopvalve in spaced relationship to said nozzle structure when said reliefvalve assemblyy is retained in said nozzle structure by the retainingmeans, and a sealing means adapted to, engage saidxnozzle structureAandgstop, valve toprevent leakage therebetweenA following; partialremoval of` said pressure, relief valve assembly.

2. The structure of claim 1 characterized in that, said lastnamedseal-ing .means isrcarried; in agroove formedson said stop valveandis oft sub.- stantiallyr circular cross-section;

3; The; structure of f claim 1 characterized' in that,I saidl nozzlestructure. isfprovided with vent means to allow escape of pressuretrapped vwithin the.,nozzle structure 4between said sealing. meansduring removal, of said pressurel relief valve-ass embly.l

4., A dual valvefconstruction comprising, a nozzle, a pressure reliefvalve assemblyy connected to. the nozzle .but removable.A therefrom, anextension carried Vby said assembly` andfextending into the nozzle toadjacent theremote end thereof, av stopvalve Acarried by 'said'remoteend of the nozzle and normally held in spacedrelation thereto ,by'said:extension when said relief valve assembly is fully connected to thenozzle structure, and seal meansoccupying the space between saidpressurereliefVA valve assemblyI and nozzle `and between said'stopvalveand nozzle to prevent leakage-of `matter past said valves duringconnection and `removal ofthe relief -valve assembly.

. 5. A duall valve construction comprising; a nozzle, a pressure reliefvalve assembly located withiny the nozzle'but removable-therefrom, anextension carried by said assembly and extending to adjacent the remoteend of the nozzle,a stop valve carried by said remote vend ofl thenozzle and held in spacedrelation ther-etc by said extension, and sealmeans occupying the space between said pressure relief valveV and'nozzleand between said stop valve and nozzle to prevent leakageof matter pastsaid valves, Vsaid seal means and valves being so constructedanclarranged that one at least'is always in constant sealing engagement withsaid nozzle during removal of said pressure relief valve assembly.

6., Adual, safety valve-construction comprising a tubular fnozzle.structure, af-,pressure relief valve assembly removably clamped ontoysaid nozzle structure adjacent one endi thereof, said-relief valvestructure.: including. a body portion positioned in said 'nozzle-.whensaid parts are assembled, said vbody portionzbeing-formedwith anannular-groove, a .circular vring ofl circular -cross section formed ofresilient materialy positioned'in said :groove and lcontacting the inner1 surface of said tubular structure, astopvalve carried bythe other:end; of saidltubular structure, said@ stop valve being formed with avertical annular extension for movement into said nozzle structureduring seating lof said valve, said extension being formed with anannular groove, a circular ring of circular cross-section formed ofresilient material positioned in said groove for contacting the innersurface of said tubular structure, spring means normally urging saidstop valve toward its seat on said nozzle structure, and means dependingfrom said relief valve body portion for holding said stop valve from itsseat against the tension of said spring means.

CLYDE H. FOLMSBEE.

JEROME M. MARTIS.

' REFERENCES CITED The following references are of record in thev fileof this patent:

5 UNITED STATES PATENTS Number Name Date 259,109 Duchemin June 6, 1882889,952 McGinley et al. June 9, 1908 l0 2,288,565 Green May 31, 1940

